Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

While annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, the description adds valuable behavioral context beyond safety: 'Scoped to your identifier (anonymous IP, BYO key hash, or account ID).' It also explains the dual behavior of retrieving a specific value vs. listing all keys when the argument is omitted, which is not fully covered by the annotations. Minor omissions (e.g., data persistence or expiration) prevent a perfect score.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences with zero filler: the first states the action, the second provides a concrete use case, and the third adds scoping and sibling links. Every sentence earns its place, and the structure is front-loaded with the core function. Excellent conciseness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool with one optional parameter, good annotations, and no output schema, the description is complete. It covers purpose, usage context, scope, and relationship to sibling tools. No critical information is missing for an agent to correctly select and invoke this tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes the 'key' parameter as 'Memory key to retrieve (omit to list all keys),' giving baseline 3 credit. The description reinforces this by saying 'omit the key argument' and adds context about the scoping and the relationship to remember/forget, enhancing understanding of the parameter's role in the workflow. This adds meaningful value beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource: 'Retrieve a value previously saved via remember, or list all saved keys.' This clearly identifies the tool's function and distinguishes it from siblings like remember and forget, which save and delete respectively. The mention of listing all keys further refines its purpose beyond a simple retrieval.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states when to use the tool: 'Use to look up context the agent stored earlier — the user's target ticker, an address, prior research notes — without re-deriving it from scratch.' It also pairs the tool with remember and forget, clarifying the workflow and implicitly guiding the agent away from alternatives. This provides strong usage context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.